1. Field of the Invention
The present invention relates to prosthetic devices, and more particularly, to prosthetic couplings having annular coupling socket adapters (aka, “pyramid receivers”) with adjustable height tube clamps.
2. Description of the Related Art
As shown in FIG. 1, an example of an above-knee (“AK”) prosthetic limb 2 for a patient may include a prosthetic limb socket 4 for receiving the wearer's residual limb, a knee joint assembly 6, a first pylon 8 coupled between the prosthetic limb socket 4 and the knee joint assembly 6, interconnection components 10 for coupling the first pylon 8 to the prosthetic limb socket 4, interconnection components 12 for coupling the first pylon 8 to the knee joint assembly 6, an ankle/foot assembly 14, and a second pylon 16 coupled between the knee joint assembly 6 and the ankle/foot assembly 14. The interconnection components 10 may consist of a locking or suction assembly 18 (such as, for example, a Shuttle Lock component commercially available from Prosthetic Design, Inc.) positioned within a distal end of the prosthetic limb socket 4, the conventional pyramidal link-plate 20, and a pyramid receiver 22 for coupling the first pylon 8 to the distal boss 24 of the pyramidal link-plate 20. Likewise, the interconnection components 12 may consist of the conventional pyramidal link-plate 20 mounted to the knee joint assembly 6 and another pyramid receiver 22 for coupling the first pylon 8 to the distal boss 24 of the pyramidal link-plate 20. The plurality of set screws 26 are tightened, thus securely mounting the pyramidal link-plate 20 to the pyramid receiver 22.
As shown in FIG. 2, a prior art prosthetic pyramid receiver 22 includes a pyramid receiver portion 30 and a diametrically restrictable tube portion 32. The tube portion 32 includes a ring-clamp 34, a screw 36 and a washer,38. The pyramid receiver portion 30 has a concave upper mouth 33 adapted to mate with the domed structure 40 of a pyramid 42. Angled holes 44 extend from the exterior surface and continue inward, thereafter extending into the interior channel of the pyramid receiver portion 30. These holes 44 are adapted to receive set screws 46 for throughput. When tightened to engage the surfaces 48 of the frustropyramidal boss 50, the pyramid 42 is pulled toward the pyramid receiver portion 30 until the domed structure 40 of the pyramid 42 engages the concave upper mouth 33 of the pyramid receiver portion 30. Thereafter, further movement between the domed structure 40 of the pyramid 42 and the concave upper portion 33 of the pyramid receiver portion 30 is minimal (collectively the elements). Further tightening of the set screws 46 increases the amount of force required axially to move the elements in relation to one another, eventually “locking” the elements together for all intents and purposes.
In fitting prosthetic limbs to patients, it is often necessary for the prosthetist to modify the lengths and/or orientations of various prosthetic limb components with respect to each other during initial fitting, or after the patient has worn the prosthetic limb for a period of time. The prosthetist attempts to maintain the alignment of the prosthetic components along the TKA line; a line parallel to the trochanter, knee and ankle. A pylon, in particular, is capable of being ground down or cut so as to shorten the length of the pylon to accord proper fitting. Problems sometimes arise when the pylon is ground down or cut, thereby shortening its length beyond that which is required. This necessitates the procurement of a completely new pylon. Alternatively, if the original pylon is too short, the current state of the art provides no alternative for the prosthetist other than procuring another pylon having a greater length.
Accordingly, there is a need for a pyramid receiver and associated tube clamp that provides axial height adjustability with respect to pylon length. Alternatively, there is a need for a system in which a prosthetist may simply exchange different height spacers or bushings to be placed within the tube of the tube clamp, between an axial shoulder in the tube and the end of the pylon, to adjust the height of the pyramid receiver with respect to the pylon.